The Ready LED Out signal is designed to pull down the cathode of an LED. The anode is attached to the proper +3.3 volt supply through an appropriate current limiting resistor. The LED and the current limiting resis- tor are external to the drive. See Table 14 for the output characteristics of the LED drive signals.

Table 14:

LED drive signal

 

 

 

 

 

State

 

Test condition

Output voltage

 

 

 

 

LED off, high

 

0 V ≤ VOH ≤ 3.6 V

-100 µA < IOH < 100 µA

LED on, low

 

IOL = 15 mA

0 ≤ VOL ≤ 0.225 V

9.5.2Differential signals

The drive SAS differential signals comply with the intra-enclosure (internal connector) requirements of the SAS standard.

Table 15 defines the general interface characteristics.

Table 15: General interface characteristics

Characteristic

Units

1.5 Gbps

3.0 Gbps

 

 

 

 

Bit rate (nominal)

Mbaud

1,500

3,000

 

 

 

 

Unit interval (UI)(nominal)

ps

666.6

333.3

 

 

 

 

Impedance (nominal, differential )

ohm

100

100

 

 

 

 

Transmitter transients, maximum

V

± 1.2

± 1.2

 

 

 

 

Receiver transients, maximum

V

± 1.2

± 1.2

 

 

 

 

9.5.2.1Eye masks

9.5.2.1.1Eye masks overview

The eye masks are graphical representations of the voltage and time limits on the signal at the compliance point. The time values between X1 and (1 - X1) cover all but 10-12of the jitter population. The random content of the total jitter population has a range of ± 7 standard deviations.

60

Barracuda ES.2 SAS Product Manual, Rev. E

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Seagate ST3750630SS, ST31000640SS, ST3500620SS LED drive signal, Differential signals, General interface characteristics
Page 63 Page 65

ST31000640SS, ST3500620SS, ST3750630SS specifications

Seagate has been a leading name in the storage industry for decades, and its range of enterprise-class hard drives showcases advanced technologies and robust performance. The Seagate ST3750630SS, ST3500620SS, and ST31000640SS are three notable models that cater to the demands of data centers and enterprises. Each model is designed with specific features that enhance reliability and efficiency, making them suitable for various applications.

The Seagate ST3750630SS is a 750GB 15K RPM Serial Attached SCSI (SAS) drive. It boasts a high-performance architecture that allows for fast data transfer rates, making it ideal for high-load environments such as transaction processing and video streaming. This drive features an MTBF of 1.6 million hours, ensuring minimal downtime due to failures. It also employs advanced error recovery and data protection mechanisms, including error correction codes (ECC), to maintain data integrity.

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The ST31000640SS is another enterprise-class offering, delivering 1TB of storage capacity. Like its counterparts, this drive operates at 15K RPM and utilizes the SAS interface, facilitating fast data processing and retrieval. It also incorporates a dual-port design which allows for redundancy and failover capabilities. This feature is critical in enterprise environments where data access and uptime are paramount. The drive's design is optimized for durability and longevity, best suited for environments that require 24/7 operation.

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